Comparison of renal cortical perfusion assessed with angiography and xenon washout technique in hydrated and dehydrated dogs: a preliminary observation.

Selective renal angiograms and xenon washout curves were performed under general anesthesia with pentobarbital in hydrated or dehydrated dogs weighing 22-27 kg. Compared to the hydrated animals a significant overall decrease in the angiographic cortical perfusion was found in the dehydrated dogs which was reversible with the infusion of 200 ml isotonic saline. The total renal blood flow, the rapid flow component and the percent of total flow to the first compartment assessed with the xenon washout technique was however not significantly different in hydrated and dehydrated animals. It is suggested that temporary cortical ischemia might occur in dehydration which differs from the well known pathologic condition of cortical ischemia since total renal blood flow appears to be normal in the former and there is a fast recovery with isotonic saline infusion. The observed findings in dehydration could be explained with redistribution of blood away from the outer cortex to the inner cortex and to the medulla.